稳压并抑制谐波的新型电源

由于电网谐波污染严重，对谐波的抑制已成为供电部门的重要任务。文章介绍一种既能稳压又能抑制谐波的新型电源，它采用串联型有源电力滤波的方法，通过瞬态电压补偿后可得到纯净的三相正弦平衡电压。     

A Digital Deformation Vacuum Gauge with an LC-Generator

The design of a sylphon bellows sensor and the basic circuits of an LC-generator and of a microprocessor unit are presented. An analytical pressure–frequency conversion function and a special method of adjusting the sensor ensure an error of less than 0.05%. The dynamic range is up to 10⁵. The instruments developed cover the ranges 10³, 10⁴, and 10⁵ Pa.     

FF现场总线的网段负载能力的设计及计算

从生产安全运行的管理要求；电压压降和电流的限制及信号的衰减；网络运行时间的要求；系统设计的影响；备用能力的考虑等各个方面，结合上海赛科聚苯乙烯项目的具体设计，分析隔爆条件下FF现场总线的H1网段负载能力的设计，以供大家探讨。     

基于调谐频率与分频处理的高分辨率反演技术

讨论了基于调谐频率与分频处理的高分辨率反演技术，给出了方法的基本原理，即利用地震数据的调谐频率和分频处理分析，半定量地确定储层厚度，并将其作为地震反演的约束条件。方法的实现过程是：通过层状地质模型的地震正演模拟，建立不同主频子波时地层厚度与调谐频率的关系；利用地震资料时-频分析技术，实现地震资料分频处理；利用合成地震记录标定地震子波主频；利用分频处理结果，借助于调谐频率分析与调谐振幅分析，给出地震反演约束条件；利用反演算法消除地震子波影响，提高和拓展地震资料的频带范围，实现储层的高分辨率成像。普光地区的应用实例表明，调谐频率与分频处理的高分辨率反演方法无需对储层空间变化规律进行假设，适用于强非均质碳酸盐岩储层的高分辨率成像。     

Range Assignment for Biconnectivity and k-Edge Connectivity in Wireless Ad Hoc Networks

Depending on whether bidirectional links or unidirectional links are used for communications, the network topology under a given range assignment is either an undirected graph referred to as the bidirectional topology, or a directed graph referred to as the unidirectional topology. The Min-Power Bidirectional (resp., Unidirectional) k-Node Connectivity problem seeks a range assignment of minimum total power subject to the constraint that the produced bidirectional (resp. unidirectional) topology is k-vertex connected. Similarly, the Min-Power Bidirectional (resp., Unidirectional) k-Edge Connectivity problem seeks a range assignment of minimum total power subject to the constraint the produced bidirectional (resp., unidirectional) topology is k-edge connected. The Min-Power Bidirectional Biconnectivity problem and the Min-Power Bidirectional Edge-Biconnectivity problem have been studied by Lloyd et al. [23]. They show that range assignment based the approximation algorithm of Khuller and Raghavachari [18], which we refer to as Algorithm KR, has an approximation ratio of at most 2(2 – 2/n)(2 + 1/n) for Min-Power Bidirectional Biconnectivity, and range assignment based on the approximation algorithm of Khuller and Vishkin [19], which we refer to as Algorithm KV, has an approximation ratio of at most 8(1 – 1/n) for Min-Power Bidirectional Edge-Biconnectivity. In this paper, we first establish the NP-hardness of Min-Power Bidirectional (Edge-) Biconnectivity. Then we show that Algorithm KR has an approximation ratio of at most 4 for both Min-Power Bidirectional Biconnectivity and Min-Power Unidirectional Biconnectivity, and Algorithm KV has an approximation ratio of at most 2k for both Min-Power Bidirectional k-Edge Connectivity and Min-Power Unidirectional k-Edge Connectivity. We also propose a new simple constant-approximation algorithm for both Min-Power Bidirectional Biconnectivity and Min-Power Unidirectional Biconnectivity. This new algorithm applies only to Euclidean instances, but is best suited for distributed implementation. A preliminary version of this work appeared in the proceedings of the 2nd International Conference on AD-HOC Network and Wireless (Adhoc-Now 2003). Research performed in part while visiting the Max-Plank-Institut fur Informatik. Gruia Calinescu is an Assistant Professor of Computer Science at the Illinois Institute of Technology since 2000. He held postdoc or visiting researcher positions at DIMACS, University of Waterloo, and Max-Plank Institut fur Informatik. Gruia has a Diploma from University of Bucharest and a Ph.D. from Georgia Insitute of Technology. His research interests are in the area of algorithms. Peng-Jun Wan has joined the Computer Science Department at Illinois Institute of Technology in 1997 and has been an Associate Professor since 2004. He received his Ph.D. in Computer Science from University of Minnesota in 1997, M.S. in Operations Research and Control Theory from Chinese Academy of Science in 1993, and B.S. in Applied Mathematics from Tsinghua University in 1990. His research interests include optical networks and wireless networks.     

江阴长江公路大桥钢箱梁体受力分析

介绍了对大桥的风向、风力和交通流量的测试依据和内容，分析了风向、风力的测试结果以及梁体在风力及交通流量等作用下的受力情况，指出钢箱梁体主要受到的力是风力。     

结构振动试验转接器的设计及安装问题

一些产品及其相关部件在作振动试验时，由于产品的外形或特殊要求不能直接安装在振动台面上，需要通过特别设计的转接器（夹具）来进行连接，这种夹具实际上是一种附加结构，它作为台面与试件之间的中介，如设置不当将影响振动试验结果的可靠性。本文通过对某事例的分析与研究，从试验频带、允许误差、跟随条件以及安装共振频率等方面阐明与讨论了相关夹具的特性、设计原则与安装等问题。     

动力环境集中监控系统可靠性的提高

为实现电源设备乃至通信机房的少人或无人值守和集中维护,必须建立一套完善的电信局动力环境集中监控系统。文中结合番禺区电信局的实际,讨论了提高系统运行可靠性的几点措施,包括硬件方面与软件方面的手段,关键在于加强系统的运行管理。     

开关电源的平均电流自动均流技术

针对多个开关电源并联时易出现负载电流在各模块间分配不均的现象,介绍了常用的负载电流自动均流法——平均电流自动均流法及其工作特性。并针对其存在母线电压降低的缺陷,提出了一种改进的平均电流自动均流方法,经试验证明均流精度比较高。     

智能组合式充电机的开发与研制

针对集中供电式地震勘探仪器在地震勘探作业中对电瓶充电的特殊要求，我们研制出一种智能组合式充电机。文中阐述了智能式充电机的设计原理，介绍了其性能指标及使用效果。